Insisting that Carlos Sainz is "a great driver", Helmut Marko claims that the Spaniard suffered as a result of being partnered with Max Verstappen early in his career.

Both making their debuts as part of Toro Rosso's all-rookie line-up in 2015, Max Verstappen has gone on to start 185 races while Carlos Sainz has 183 to his name.

However, as far as statistics are concerned that is as close as it gets, the Dutchman has gone on to win three titles, 54 grands prix, claim 33 pole positions and post 30 fastest laps. Thus far, Sainz has claimed 2 wins, 4 poles and 3 fastest laps.

According to Helmut Marko, being partnered with Verstappen so early in his career was damaging to Sainz who, according to the Austrian, was unlucky to be matched with such a mercurial talent.

In that first season, Verstappen scored 49 points and finished 12th in the standings, his best results being a brace of fourths in Hungary and the United States, while his Spanish teammate scored just 18 points, a seventh at the Circuit of the Americas being his best finish.

In the opening races of 2016 Verstappen scored a sixth in Bahrain, and when, ahead of the Spanish Grand Prix, it was felt that Daniil Kvyat was out of his depth at Red Bull it was the Dutchman who was promoted to the vacant Red Bull seat.

Winning on his debut for the Austrian team the Dutchman went on to finish 5th in the championship, while it was a year later that Sainz made the early switch to Renault to replace Jolyon Palmer.

While Verstappen has remained with Red Bull, Sainz went from Renault to McLaren and finally to Ferrari, with whom he finally scored his first win.

While In no doubt about the Spaniard's talent, Marko insists that it was the right decision to maintain the status quo at Red Bull.

"Sainz is, without a doubt, a great driver," he tells Marca. "He was almost on par with Max in the Toro Rosso. The bad thing for him is that he was unlucky to have Verstappen as a team-mate.

"The atmosphere between the two in the team was quite toxic," reveals the Austrian. "The way the team was set up at the time, I didn't see a way to keep him with us, so Carlos went to Renault, to McLaren and then ended up at Ferrari."

Marko also reveals that at his first F1 test it was clear that Sainz had pace, the Spaniard faster in the high-speed sections at Silverstone than the reigning world champion, Sebastian Vettel.

"He was very fast in the minor categories. In his first F1 test at Silverstone, right from the start, he was slightly quicker in the fast corners than Sebastian Vettel, who was our reference at that moment.

"He was almost at the same level as Verstappen, almost, but when we had to choose between Max and Carlos, it was clear what we had to do."

Other than Verstappen, Marko opines that the Spaniard was perhaps overshadowed by another driver... his father, who only this weekend won the Dakar Rally at the age of 61.

"For a long time Carlos lived in his father's shadow," says Marko. "He was unfairly burdened with the image of being the spoiled son of a racing driver while, on the contrary, he had to constantly fight to get ahead."